President Rodrigo Duterte is "robust enough" to travel to Japan this week, Malacanang said on Monday.

Presidential Spokesperson Salvador Panelo made the statement amid concerns about Duterte's health after he delegated to Defense Secretary Delfin Lorenzana the distribution of diplomas to the 261 graduates of the Philippine Military Academy during commencement exercises in Baguio City on Sunday.

"To those who are concerned about his well being, they should be assured that apart from what he already told the public of what ails him (which is not life threatening) the President is in good health, robust enough to be travelling to Japan for an official visit upon the invitation of Prime Minister (Shinzo) Abe," Panelo said.

Duterte is set to leave for Tokyo on Tuesday afternoon. This will be his third visit to Japan since he assumed office in 2016.

He was invited by Nikkei to attend its conference on May 30 to 31.

Duterte is set to speak in the forum on May 31, the Department of Foreign Affairs earlier said.

After his speech, Duterte will have a bilateral meeting with Abe, the DFA has said.

In the press briefing last week in Malacanang, DFA Assistant Secretary Meynardo Montealegre said Duterte's summit meeting with Abe would be their seventh since 2016.

He said the coming meeting of the two leaders would be an opportunity for them to further strengthen the two countries' strategic partnership in areas such as defense, security, economic cooperation, infrastructure development, the entry of Filipino skilled workers to Japan, and Japanese assistance for the development of the Bangsamoro region.

The two leaders are also expected to exchange views on regional issues of mutual concern including the Korean Peninsula and the South China Sea, he has said.

Duterte might meet the Filipino community in Japan.

He will be accompanied by some members of his Cabinet and some Filipino businessmen. Celerina Monte/DMS